<template>
	<div class="upload-file">
		<el-upload
			multiple
			:action="uploadFileUrl"
			:before-upload="handleBeforeUpload"
			:file-list="fileList"
			:limit="limit"
			:on-error="handleUploadError"
			:on-exceed="handleExceed"
			:on-success="handleUploadSuccess"
			:show-file-list="false"
			:headers="headers"
			class="upload-file-uploader"
			ref="fileUpload"
		>
			<!-- 上传按钮 -->
			<el-button size="mini" type="primary">选取文件</el-button>
			<!-- 上传提示 -->
			<div class="el-upload__tip" slot="tip" v-if="showTip">
				请上传
				<template v-if="fileSize">
					大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b>
				</template>
				<template v-if="fileType">
					格式为 <b style="color: #f56c6c">{{ fileType.join('/') }}</b>
				</template>
				的文件
			</div>
		</el-upload>

		<!-- 文件列表 -->
		<transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
			<li :key="file.url" class="el-upload-list__item ele-upload-list__item-content" v-for="(file, index) in fileList">
				<el-link :href="`${baseUrl}${file.url}`" :underline="false" target="_blank">
					<span class="el-icon-document"> {{ getFileName(file.name) }} </span>
				</el-link>
				<div class="ele-upload-list__item-content-action">
					<el-link :underline="false" @click="handleDelete(index)" type="danger">删除</el-link>
				</div>
			</li>
		</transition-group>
	</div>
</template>

<script>
import { getToken } from '@/utils/auth';

export default {
	name: 'FileUpload',
	props: {
		// 值
		value: [String, Object, Array],
		// 数量限制
		limit: {
			type: Number,
			default: 5,
		},
		// 大小限制(MB)
		fileSize: {
			type: Number,
			default: 5,
		},
		// 文件类型, 例如['png', 'jpg', 'jpeg']
		fileType: {
			type: Array,
			default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf'],
		},
		// 是否显示提示
		isShowTip: {
			type: Boolean,
			default: true,
		},
	},
	data() {
		return {
			number: 0,
			uploadList: [],
			baseUrl: process.env.VUE_APP_BASE_API,
			uploadFileUrl: process.env.VUE_APP_BASE_API + '/common/upload', // 上传文件服务器地址
			headers: {
				Authorization: 'Bearer ' + getToken(),
			},
			fileList: [],
		};
	},
	watch: {
		value: {
			handler(val) {
				if (val) {
					let temp = 1;
					// 首先将值转为数组
					const list = Array.isArray(val) ? val : this.value.split(',');
					// 然后将数组转为对象数组
					this.fileList = list.map((item) => {
						if (typeof item === 'string') {
							item = { name: item, url: item };
						}
						item.uid = item.uid || new Date().getTime() + temp++;
						return item;
					});
				} else {
					this.fileList = [];
					return [];
				}
			},
			deep: true,
			immediate: true,
		},
	},
	computed: {
		// 是否显示提示
		showTip() {
			return this.isShowTip && (this.fileType || this.fileSize);
		},
	},
	methods: {
		// 上传前校检格式和大小
		handleBeforeUpload(file) {
			// 校检文件类型
			if (this.fileType) {
				const fileName = file.name.split('.');
				const fileExt = fileName[fileName.length - 1];
				const isTypeOk = this.fileType.indexOf(fileExt) >= 0;
				if (!isTypeOk) {
					this.$modal.msgError(`文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`);
					return false;
				}
			}
			// 校检文件大小
			if (this.fileSize) {
				const isLt = file.size / 1024 / 1024 < this.fileSize;
				if (!isLt) {
					this.$modal.msgError(`上传文件大小不能超过 ${this.fileSize} MB!`);
					return false;
				}
			}
			this.$modal.loading('正在上传文件，请稍候...');
			this.number++;
			return true;
		},
		// 文件个数超出
		handleExceed() {
			this.$modal.msgError(`上传文件数量不能超过 ${this.limit} 个!`);
		},
		// 上传失败
		handleUploadError(err) {
			this.$modal.msgError('上传文件失败，请重试');
			this.$modal.closeLoading();
		},
		// 上传成功回调
		handleUploadSuccess(res, file) {
			if (res.code === 200) {
				this.uploadList.push({ name: res.fileName, url: res.fileName });
				this.uploadedSuccessfully();
			} else {
				this.number--;
				this.$modal.closeLoading();
				this.$modal.msgError(res.msg);
				this.$refs.fileUpload.handleRemove(file);
				this.uploadedSuccessfully();
			}
		},
		// 删除文件
		handleDelete(index) {
			this.fileList.splice(index, 1);
			this.$emit('input', this.listToString(this.fileList));
		},
		// 上传结束处理
		uploadedSuccessfully() {
			if (this.number > 0 && this.uploadList.length === this.number) {
				this.fileList = this.fileList.concat(this.uploadList);
				this.uploadList = [];
				this.number = 0;
				this.$emit('input', this.listToString(this.fileList));
				this.$modal.closeLoading();
			}
		},
		// 获取文件名称
		getFileName(name) {
			// 如果是url那么取最后的名字 如果不是直接返回
			if (name.lastIndexOf('/') > -1) {
				return name.slice(name.lastIndexOf('/') + 1);
			} else {
				return name;
			}
		},
		// 对象转成指定字符串分隔
		listToString(list, separator) {
			let strs = '';
			separator = separator || ',';
			for (let i in list) {
				strs += list[i].url + separator;
			}
			return strs != '' ? strs.substr(0, strs.length - 1) : '';
		},
	},
};
</script>

<style scoped lang="scss">
.upload-file-uploader {
	margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
	border: 1px solid #e4e7ed;
	line-height: 2;
	margin-bottom: 10px;
	position: relative;
}
.upload-file-list .ele-upload-list__item-content {
	display: flex;
	justify-content: space-between;
	align-items: center;
	color: inherit;
}
.ele-upload-list__item-content-action .el-link {
	margin-right: 10px;
}
</style>
